Electrical stimulation lead, system, and method

ABSTRACT

In one embodiment, a paddle lead comprises: a plurality of stimulating electrode contacts disposed, the plurality of stimulation electrode contacts being adapted to allow the stimulation paddle to flex transversely about a longitudinal axis; wherein the plurality of stimulation electrode contacts are arranged in at least first, second, and third rows that are disposed perpendicular to a longitudinal axis of the paddle; the first and third rows respectively having multiple electrode contacts electrically coupled to different conductors of the lead to enable the multiple electrode contacts of the first and third rows to function in independent cathode states, anode states, or high-impedance states; the second row being disposed between the first and third rows, the second row having multiple electrode contacts each electrically coupled to a common conductor to cause the multiple electrode contacts of the second row to function in a common cathode state, anode state, or high-impedance state.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/671,977, filed Apr. 14, 2005, entitled“ELECTRICAL STIMULATION LEAD, SYSTEM, AND METHOD,” which is incorporatedherein by reference.

TECHNICAL FIELD

The present application is generally related to electrical stimulationfor medical purposes and, in particular, to an electrical stimulationlead, system, and method.

BACKGROUND

Electrical energy may be applied to a person's spinal cord to treat avariety of clinical conditions, such as chronic pain. For example,electrical energy may be applied to the spinal cord to cause asubjective sensation of numbness or tingling in an affected region ofthe body, known as “paresthesia.” The electrical energy is deliveredthrough stimulating electrodes positioned proximate the spinal cordtissue targeted for stimulation. The stimulation electrodes may becarried by either two primary vehicles: a percutaneous lead or alaminotomy, surgical, or “paddle” lead. Percutaneous leads arepositioned using a needle that is passed through the skin and into theepidural space adjacent the spinal cord such that the stimulatingelectrodes are proximate nerve tissue targeted for stimulation.Percutaneous leads deliver energy generally radially in all directionsbecause of the circumferential nature of the stimulation electrodes.Paddle leads have a paddle-like configuration and typically have anumber of directional stimulation electrodes arranged in one or morecolumns. Paddle leads may provide more focused energy delivery thanpercutaneous leads because the directional stimulating electrodes may bepresent on only one surface of the lead. Paddle leads may be desirablein certain situations because they may provide more direct stimulationto targeted nerve tissue and may require less energy to produce adesired effect. Directional stimulating electrodes of paddle leads maybe arranged to provide anode guarding or blocking to more specificallydirect stimulation to targeted nerve tissue.

SUMMARY

The electrical stimulation lead, system, and method of some embodimentsof the invention may reduce or eliminate certain problems anddisadvantages associated with prior techniques for electricallystimulating spinal cord tissue.

According to one aspect, an electrical stimulation portion adapted forimplantation in a person's body to provide therapeutic electricalstimulation of target spinal cord tissue includes a plurality ofstimulating electrode contacts that are integrated on a first face ofthe stimulation portion and are adapted for implantation in the person'sbody with the stimulating portion. The plurality of stimulationelectrode contacts are operable to provide electrical stimulation totarget spinal cord tissue. The plurality of stimulation electrodecontacts comprise at least one stimulating electrode contact having afirst contact area and at least one traverse array of stimulatingelectrode contacts. Each traverse array comprises a plurality ofstimulating electrode contacts aligned in a row and spaced apart fromeach other in a direction approximately perpendicular to a longitudinalaxis of the stimulation portion. Each of the stimulating electrodecontacts of the at least one traverse array have a second contact areano greater than three-fourths of the first contact area. The stimulationportion includes one or more terminals each coupled to one or morerespective stimulating electrode contacts of the plurality ofstimulating electrode contacts and adapted to transmit electric currentto its one or more respective stimulating electrode contacts.

Particular embodiments may provide one or more advantages. For example,some embodiments provide an electrical stimulating portion having atransverse array of stimulating electrode contacts that are aligned in arow in a direction perpendicular to a longitudinal axis of thestimulation portion and that are smaller than other stimulatingelectrode contacts of the lead to increase the ability of thestimulating portion to flex or bend transversely about the longitudinalaxis of the stimulation portion. In addition, some embodiments include aplurality of grooves on an opposite face of the stimulating portion thatprovide further flexibility. The increased ability of the stimulatingportion to flex or bend transversely about a longitudinal axis of thestimulating portion enables an operator of the stimulating portion tomore easily implant and position the stimulating portion withoutdamaging the lead or spinal cord tissue. This also increases comfort tothe patient during use.

In one embodiment, a paddle lead comprises: a plurality of stimulatingelectrode contacts disposed on a first side of a stimulation paddle ofthe stimulation lead, the plurality of stimulation electrode contactsbeing adapted to allow the stimulation paddle to flex transversely aboutthe longitudinal axis; a plurality of conductors for conductingelectrical energy to the plurality of stimulating electrode contacts;wherein the plurality of stimulation electrode contacts are arranged inat least first, second, and third rows that are disposed perpendicularto a longitudinal axis of the stimulation paddle; the first and thirdrows respectively having multiple electrode contacts electricallycoupled to different conductors of the plurality of conductors to enablethe multiple electrode contacts of the first and third rows to functionin independent cathode states, anode states, or high-impedance states;the second row being disposed between the first and third rows, thesecond row having multiple electrode contacts each electrically coupledto a common conductor of the plurality of conductors to cause themultiple electrode contacts of the second row to function in a commoncathode state, anode state, or high-impedance state.

The foregoing has outlined rather broadly certain features and/ortechnical advantages in order that the detailed description that followsmay be better understood. Additional features and/or advantages will bedescribed hereinafter. It should be appreciated by those skilled in theart that the conception and specific embodiment disclosed may be readilyutilized as a basis for modifying or designing other structures forcarrying out the same purposes. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the appended claims. The novel features, both asto organization and method of operation, together with further objectsand advantages will be better understood from the following descriptionwhen considered in connection with the accompanying figures. It is to beexpressly understood, however, that each of the figures is provided forthe purpose of illustration and description only and is not intended asa definition of the limits of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of some embodiments of the inventionand advantages thereof, reference is now made to the followingdescription taken in conjunction with the accompanying drawings.

FIGS. 1A-1B depict example neurological stimulation systems forelectrically stimulating a person's spinal cord tissue to treat one ormore clinical conditions.

FIGS. 2A-2C illustrate an example stimulation lead that may be used toelectrically stimulate a person's spinal cord tissue to treat one ormore clinical conditions.

FIG. 3 illustrates a stimulating portion that may be used toelectrically stimulate a person's spinal cord tissue to treat one ormore clinical conditions showing example electrode contact wiringconnections.

FIG. 4 illustrates an example method of implanting the stimulationsystems of FIGS. 1A and 1B into a person's body with a stimulation leadlocated proximate spinal cord tissue for electrical stimulation to treatone or more clinical conditions.

FIGS. 5-7 depict respective stimulation paddle designs according toalternative embodiments.

DETAILED DESCRIPTION

According to one representative embodiment, a neurological stimulationsystem 10 is used to electrically stimulate target tissue in a person'sspinal cord to treat one or more clinical conditions, such as chronicpain. In general, an electrical stimulation lead with stimulationelectrodes that include stimulating electrode contacts is implantedsubcutaneously such that the stimulation electrode contacts are locatedproximate the target spinal cord tissue. As used herein, the term“proximate” means on, in, adjacent, or near. Thus, the stimulationelectrode contacts of a stimulation lead are adapted to be positionedon, in adjacent, or near the target spinal cord tissue. In general, thestimulation electrode contacts proximate the spinal cord tissue deliverelectrical stimulation pulses to the tissue, which thereby permanentlyor temporarily eliminates, reduces, or otherwise treats the one or moreclinical conditions. This may in turn significantly increase theperson's quality of life.

FIGS. 1A-1B illustrate example neurological systems 10 for electricallystimulating target spinal cord tissue to treat one or more clinicalconditions, such as chronic pain. In general terms, stimulation system10 includes a stimulation pulse generating portion (for example,implantable electrical stimulation source 12) and one or moreimplantable stimulation pulses to the target spinal cord tissue. Inoperation, both of these primary components are implanted in theperson's body. In certain embodiments, stimulating source 12 is coupleddirectly to a connecting portion 16 of stimulation lead 14. In certainother embodiments, stimulating source 12 is not coupled directly tostimulating lead 14. For example, in a microstimulator, a stimulationsource 12 instead is integrated and communicates with a stimulatingportion, that may incorporate, one or more electrodes to the stimulatingportion. One example in the art of such a microstimulator is the Bion®microstimulator manufactured by Advanced Bionics Corporation, whileother microstimulators are known. Whether stimulation source 12 iscoupled directly or indirectly to stimulation lead 14, stimulationsource 12 controls the stimulation pulses transmitted to one or morestimulation electrodes 18 located on a stimulation portion 20 ofstimulation lead 14, positioned proximate the target spinal cord tissue,according to suitable stimulation parameters (e.g., duration, amplitudeor intensity, frequency, pulse width, etc.). A doctor, the patient, oranother user of stimulation source 12 may directly or indirectly inputstimulation parameters to specify or modify the nature of thestimulation provided to the patient.

In one embodiment, as shown in FIG. 1A, stimulation source 12 includesan implantable pulse generator (IPG). An example IPG may be incorporatedin the Genesis® system or the Eon® system manufactured by AdvancedNeuromodulation Systems, Inc. In another embodiment, as shown in FIG.1B, stimulation source 12 includes an implantable wireless receiver. Anexample wireless receiver may be one incorporated in the Renew® systemmanufactured by Advanced Neuromodulation Systems. The wireless signalsare represented in FIG. 1B by wireless link symbol 24. A doctor, thepatient, or another user of stimulation source 12 may use a controller26 located external to the person's body to provide control signals towireless transmitter 22, wireless transmitter 22 transmits the controlsignals and power to the wireless receiver of stimulation source 12, andstimulation source 12 uses the control signals to vary the stimulationparameters of stimulation pulses transmitted through stimulation lead 14to the target spinal cord tissue. An example of wireless transmitter 22may be one incorporated in the Renew® system manufactured by AdvancedNeuromodulation Systems.

Although specific stimulation systems have be provided as examples, anyappropriate circuitry can be employed to generate suitable stimulationpulses for electrically stimulating the target spinal cord tissue usingleads 14 according to some representative embodiments. Example ofsuitable circuitry for generating stimulation pulses is described inU.S. Pat. No. 6,609,031, which is hereby incorporated by reference as iffully illustrated and described herein.

FIG. 2A illustrates an example stimulation lead 14 that may be used forelectrically stimulating nerve tissue in a person's spinal cord to treatone or more clinical conditions, such as chronic pain. As describedabove, stimulation lead 14 includes stimulation electrodes 18. Eachstimulation electrode 18 includes one or more stimulation electrodecontacts adapted to be positioned proximate target spinal cord tissueand used to deliver to the target spinal cord tissue stimulation pulsesreceived from stimulation source 12. Stimulation lead 14 may be referredto as a laminotomy, surgical, or paddle stimulation lead. The electrodecontacts forming electrodes 18 are spaced apart from one another alongone surface of stimulation portion 20. In particular embodiments,electrode contacts are separated from each other by one or moreinsulative materials. An insulative material of a stimulation lead maycomprise an insulating, dielectric, or other material having a lowerconductivity that a metal or other material used for form thestimulation electrode contacts of stimulation lead 14.

Stimulation lead 14 also includes one or more terminals 20 coupled tostimulation source 12 (illustrated in FIGS. 1A and 1B). Each terminal 20is also coupled to one or more electrode contacts using electricalconductors running through stimulation lead 14 to transmit stimulationpulses to the electrode contacts. As discussed below, in the illustratedembodiment, electrodes 18 d and 18 f each comprise three electrodecontacts spaced apart from each other and separated by one or moreinsulative materials. In this case, one terminal 20 may be coupled toeach of the three electrode contacts operatively set to function as oneelectrode 18 d and 18 f. For example, terminal 20 d may be coupled tothe three electrode contacts forming stimulation electrode 18 d andterminal 20 f may be coupled to the three electrode contacts formingstimulation electrode 18 f. The selection of the particular electrodecontacts forming particular electrodes 18 to which particular terminals20 are coupled may be made in any suitable manner to satisfy theobjectives in particular embodiments. As illustrated, the electrodecontacts of stimulation lead 14 are set to function as eight separateelectrodes (18 a-18 h). In some embodiments, each electrode contact of astimulation lead may be set to operate as a separate electrode. Forexample, with respect to stimulating portion 20, each of the threeelectrode contacts of electrode 18 d and each of the three electrodecontacts of electrode 18 f could be set to operate as separateelectrodes. Thus, those six electrode contacts could operate as sixseparate electrodes. If each electrode contact of stimulation lead 14were set to operate as a separate electrode (with corresponding changesin wiring and the number of terminals 20), then the illustratedstimulation lead 14 would have twelve separate electrodes.

Electrode contacts forming electrodes 18 emit electrical stimulationenergy received from stimulation source 12 in a direction generallyperpendicular to the surface of stimulation lead 14 on which they arelocated. In operation, at any particular time, each electrode 18 may beprogrammed, configured, or otherwise set as an anode (+), as a cathode(−), or in an “off” state. An electrical current “flows” from an anodeto a cathode. Consequently, a range of simple to complex electricalfields can be created by setting electrode contacts in variouscombinations of anodes, cathodes, and “off” states.

In the illustrated embodiment, electrodes 18 d and 18 f each comprise atraverse array of three electrode contacts aligned in a row in adirection approximately perpendicular to longitudinal axis 19 ofstimulation lead 14. Thus, stimulation electrode 18 d comprises threeseparate electrode contacts connected to operate as one electrode, andstimulation electrode 18 f comprises three separate electrode contactsconnected to operate as one electrode. In the illustrated embodiment,the electrode contacts of the stimulation lead generally have an oblongshape. In addition, each electrode contact of electrodes 18 d and 18 fare approximately three-fourths the size (e.g., as measured by thesurface area of the electrode contact) of the oblong electrode contactsforming electrodes 18 a, 18 b, and 18 c, 18 e, 18 g, and 18 h.Particular embodiments may include a stimulation lead with electrodecontacts having any suitable shapes and sizes, which may be uniform ordifferent, according to particular needs. Some embodiments may include astimulation lead 14 having electrode contacts that are at least two tofour times the size of other electrode contacts of the stimulation lead14.

In certain embodiments, the use of multiple separate electrode contactsto act as a single electrode 18 and arranged across stimulation lead 14enhances the ability of stimulation lead 14 to bend or flex, such astransversely across longitudinal axis 19 of stimulation lead 14. Ifelectrode 18 d, for example, comprised a single electrode contactarranged across the paddle-shaped stimulating portion in a perpendicularrelationship to electrodes 18 a, 18 b, 18 c, 18 e, 18 g, and 18 h, thenstimulation lead 14 would be less able to bend or flex transverselyabout longitudinal axis 19. In addition, the separate electrode contactsof electrodes 18 d and 18 f in the illustrated embodiment are aligned inrows across stimulation portion 20 to further enhance the ability ofstimulation lead 14 to bend or flex transversely about longitudinal axis19. Particular embodiments may include electrode contacts arranged inany suitable manner to provide increased flexibility of stimulation lead14 as appropriate or desired.

In certain embodiments, electrodes 18 may be set and arranged asappropriate to provide anode guarding or blocking. As indicated above,current flows from an anode to a cathode. An anode guard functions, inpart, to laterally limit an applied electrical field to assist inreducing extraneous stimulation of spinal cord and other tissuesurrounding the target spinal cord tissue. In certain embodiments, sincea cathode electrode 18 provides the actual stimulation of the targetspinal cord tissue (i.e., stimulation occurs at or neat the cathode),one or more anode electrodes 18 may be positioned around or otherwiserelative to one or more cathode electrodes 18 to focus an appliedelectrical field in the vicinity of the one or more cathode electrodes18. Thus, electrodes 18 set and arranged to provide anode guarding orblocking may enable stimulation lead 14 to apply more focused andtherapeutically effective stimulation energy than applied if electrodeswere otherwise set or arranged. Setting electrodes 18 to provide anodeguarding or blocking may comprise setting individual electrodes 18 ascathodes or anodes in a manner sufficient to provide such functionality,and arranging electrodes 18 to provide anode guarding or blocking maycomprise positioning electrodes 18 on stimulation lead 14 in a mannersufficient to provide such functionality.

As indicated above, in particular embodiments, separate electrodecontacts may be programmed to function as separate electrodes. Inaddition, any number of separate electrode contacts may be combined tooperate as a single electrode in any suitable manner (e.g., as the threeseparate electrode contacts of electrode 18 f are adapted to operate asa single electrode). The ability to, as is desired, to program separateelectrode contacts to operate as one or more electrodes, whether set ascathodes, anodes, or in high impedance, open circuit or “off state,”provides great flexibility in stimulating options, particular withrespect to anode guarding or blocking functionality.

FIG. 2B is an illustration of stimulation lead 14 that shows theunderside of stimulation portion 20, or the opposite side of stimulationportion 20 from that shown in FIG. 2A. Stimulating portion 20 includesgrooves 21 running the length L of stimulation portion 20. Grooves 21reduce the area of the underside of stimulating portion 20 contactingtissue. In certain embodiments, grooves 21 aid in stabilizingstimulation lead 14 laterally when stimulation lead is being implantedproximate target spinal cord tissue and thereafter. For example, grooves21 may help prevent stimulation lead 14 from veering to one side or theother as stimulation lead 14 is advanced along the dorsal column midlineduring implantation and may further help prevent stimulation lead 14from slipping to one side of the dorsal column midline stimulation lead14 has been implanted and thereafter. In certain embodiments, grooves 21also further enable stimulation lead 14 to bend or flex transverselyabout longitudinal axis 19. While five grooves 12 are shown, particularembodiments may include any number of grooves 21 arranged in anysuitable manner. Preferably, multiple grooves 21 are transverselypositioned coincident with the portions of the paddle face that do notinclude electrical contacts, thereby facilitating the flexingcharacteristics of lead 14. In an alternative embodiment, grooves 21 canbe filled or replaced with longitudinal segments of a polymer materialhaving a reduced durometer relative to insulative material of theremaining portion of the paddle. The selection of the durometer for thelongitudinal segments of material can be made to facilitate transverseflexing of the paddle.

FIG. 2C is a cross-sectional view of stimulating portion 20 taken alongline 2C-2C of FIG. 2B. As illustrated, grooves 21 are formed as roundcut-outs of stimulation portion 20. However, other embodiments mayinclude grooves 21 having other suitable shapes or configurations.

FIG. 3 illustrates a stimulating portion 50 that may be used toelectrically stimulate a person's spinal cord tissue to treat one ormore clinical conditions showing example electrode contact wiringconnections. Stimulation portion 50 may be similar to stimulatingportion 20 described above in regard to FIGS. 1A, 1B, 2A, 2B and 2C.Stimulation source 50 includes stimulation electrode contacts 60-71having varying shapes and sizes. In the illustrated embodiment,electrode contacts 60-62 and 66-68 are generally round and each have asize approximately three-fourths the size of each oblong electrodecontact 63-65 and 69-71.

The illustrated embodiment includes electrical conductors 80 a-80 hcoupled to electrode contacts 60-71. Electrical conductors 80 a-80 h maybe coupled to terminals coupled to a stimulation source, such asterminals 20 a-20 h, respectively of FIGS. 2A and 2B. Electricalconductors 80 a-80 h transmit stimulation pulses from a stimulationsource to electrode contacts 60-71. The actual connections of electricalconductors to electrode contacts may implemented in any suitable manner,such as physically connecting electrode conductors to portions ofelectrode contacts on the underside of such contacts exposed through theunderside of stimulation face of stimulation portion 50.

As indicated above, electrode contacts of a stimulating portion inaccordance with various embodiments may be coupled to terminals in anysuitable manner. FIG. 3 illustrates one example of such coupling. Asillustrated, electrical conductor 80 a is coupled to electrode contact69; electrical conductor 80 b is coupled to electrode contact 63;electrical conductor 80 c is coupled to electrode contact 70; electricalconductor 80 d is coupled to electrode contact 66; electrical conductor80 e is coupled to electrode contact 64; electrical conductor 80 f iscoupled to electrode contact 62; electrical conductor 80 g is coupled toelectrode contact 71; and electrical conductor 80 h is coupled toelectrode contact 65.

In addition, stimulation portion includes conductors 82 a-82 b and 84a-84 b. Electrical conductor 82 a couples electrode contact 66 withelectrode contact 67 and electrical conductor 82 b couples electrodecontact 67 with electrode contact 68. Thus, since electrode contacts66-68 are each coupled together (e.g., through electrical conductors 80d, 82 a, and 82 b), they may be operatively set to function as oneelectrode. In addition, electrical conductor 84 a couples electrodecontact 61 with electrode contact 62 and electrical conductor 84 bcouples electrode contact 60 with electrode contact 61. Thus, sinceelectrode contacts 60-62 are each coupled to together (e.g., throughelectrical conductors 80 f, 84 a, and 84 b), they may be operatively setto function as one electrode.

Thus, the wiring of the illustrated embodiment is such that stimulationportion 50 includes electrode contacts that may function as eightseparate electrodes. Electrode contacts 63-65 and 69-71 may function assix separate electrodes. Electrode contacts 63-65 and 69-71 may functionas a single electrode and electrode contacts 66-68 may function as asingle electrode. As indicated above, stimulating portions of otherembodiments may include electrode contacts wired to function as anynumber or type of electrodes.

FIG. 5 depicts an alternative paddle design according to onerepresentative embodiment. As shown in FIG. 5, paddle lead 500 compriseselectrode contacts 18 a, 18 b, 18 c, 18 e, 18 h, and 18 g implemented insubstantially the same manner as the electrode contacts of stimulationportion 20 shown in FIG. 2A. Each of these electrode contacts arepreferably separately coupled to different conductors of the lead toallow these contacts to independently function in cathode, anode, orhigh impedance states. Preferably, grooves 21 (previously shown in FIG.2B) are disposed on the other side of paddle lead 500 to facilitate theflexibility of the paddle structure of lead 500.

The electrode contact design of paddle lead 500 differs from the designshown in FIG. 2A with regard to the electrode contacts intended toperform anodal blocking. Specifically, electrodes 510 a and 510 b arerespectively formed of three separate bar-shaped electrode contacts. Theseparate electrode contacts occupy more surface area than thecorresponding electrode contacts of stimulation portion 20. However, theseparate electrode contacts are spaced apart by sufficient space toenable the paddle structure to transversely flex at locations 501 and502. To electrically couple each of the separate electrode contactstogether, a trace or strip of flexible conductive epoxy 510 is placedbetween the separate electrode contacts. Additionally, the trace orstrip of epoxy material 510 is oriented in a transverse direction on thepaddle structure to facilitate the flexibility of the paddle atlocations 501 and 502. The traces or strips 510 of conductive epoxy canbe overlaid with suitable bio-compatible, bio-stable polymer dependingupon the characteristics of the selected epoxy material.

A thin film conductor can be utilized for traces or strips 510 accordingto an alternative embodiment. The thin film conductor traces can beformed in multiple layers. For example, a first thin metal layer can beformed on the polymer substrate of the paddle structure using titanium,chromium, aluminum or nickel. To enhance adherence of this coating tothe polymer material, the coating is either concurrently bombardedduring its deposition by high energy ions, which serve to “shot-peen”the film layer into the surface of the polymer and to continuously breakup the coating from an amorphous/columnar structure to a nanocrystallinestructure, exhibiting over-lapping platelet regions. The concurrentbombardment is commonly referred to by the acronym “IBAD” for ion beamassisted deposition. Alternatively, so-called ion beam enhanceddeposition or IBED may be used where ion beam bombardment is appliedsubsequent to the deposition of the metallic layer.

A second thin metal film layer or coating is subsequently deposited overthe first layer using palladium or platinum to function as aself-alloying/oxygen diffusion barrier layer. The deposition preferablytakes place in the presence of high energy ions to enhance stitchingbetween the base layer and the second layer to provide a desiredstress-free and non-columnar structure. A third metal film layer is thenapplied to a predetermined thickness to function as a bulk conductivelayer. The third metal layer preferably comprises platinum or silver oranother similar conductive element or alloy. A final bio-compatible,bio-stable conductive layer is applied for exposure to the tissue of thepatient. By minimizing the thickness of the conductive traces and byorienting the traces transversely on the paddle, paddle lead 600 is ableto flex about locations 501 and 502.

FIG. 6 depicts paddle lead 600 according to another representativeembodiment. Paddle lead 600 is preferably implemented in a manner thatis substantially similar to paddle lead 500 except paddle lead 600includes multiple rows 601, 602, and 602 of independent electrodecontacts (in this embodiment, there are five independent electrodecontacts per row). FIG. 7 depicts paddle lead 700 that is substantiallythe same as paddle lead 600 except that paddle lead 700 compriseslongitudinal electrode contacts 701 on the edges of the paddle structureto perform lateral anode blocking as appropriate for a given therapeuticapplication. The multiple rows 601, 602, and 603 of paddle leads 600 and700 are advantageous in that the various rows can be used substantiallyindependently to address complex pain patterns in a substantiallysimultaneous manner. For example, row 601 could be utilized to treatchronic pain in a first limb and row 603 could be utilized to treatchronic pain in a second limb. Anodal blocking may occur between the tworows 601 and 603 to substantially cause the electrical fields associatedwith those rows to be independent from each other. Additionally, thegreater number of electrodes in a given row enables greater freedom insteering an applied electrical field in the transverse direction asnecessary for a particular patient and pain condition.

FIG. 4 illustrates an example method of implanting stimulating system 10of FIGS. 1A-1B into a person's body with stimulation lead 14 locatedproximate target spinal cord tissue for electrical stimulation to treatone or more clinical conditions, such as chronic pain. At step 30,stimulation lead 14 is implanted such that one or more electrodes 18 ofstimulation lead 14 are positioned proximate target spinal cord tissue.Techniques for implanting stimulation leads such as stimulation lead 14are known to those skilled in the art. At step 32, stimulation source 12may be coupled directly to connecting portion 16 of stimulation lead 14.Alternatively, as described above, stimulation source 12 may not becoupled directly to stimulation lead 14 and may instead be coupled tostimulation lead 14 via a wireless link.

Intra-implantation trial stimulation may be conducted at steps 34-38.Alternatively, the method may proceed from step 32 to 40. At step 34,stimulation source 12 is activated to generate and transmit stimulationpulses to the target spinal cord tissue via one or more electrodes 18 ofstimulation lead 14 positioned proximate the target spinal cord tissue.At step 36, subjective or objective testing and analysis may beperformed to determine whether one or more clinical conditions aresufficiently improved, one or more stimulation patterns may be adjusted,stimulation lead 14 may be moved incrementally or even re-implanted, orboth of these modifications may be made at step 38 and the trialstimulation and analysis repeated until the one or more clinicalconditions are sufficiently improved. Once the stimulation parametershave been properly set and stimulation lead 14 has been properlypositioned such that the one or more clinical conditions aresufficiently improved, intra-implantation trial stimulation is complete.

Once stimulation lead 14 has been properly implanted and secured, andany trial stimulation completed, stimulation source 12 is implanted asstep 40. Techniques for implanting stimulation source 12 are known tothose skilled in the art. The implant site is typically a subcutaneouspocket formed to receive and house stimulation source 12. The implantsite is usually located some distance away from the insertion site, suchas in or near the upper chest or buttocks. Where stimulation lead 14includes connecting portion 16, connecting portion 16 is tunneled, atleast in part, subcutaneously to the implant site of stimulation source12 at step 42. At step 44, a doctor, the patient, or another user ofstimulation source 12 may directly or indirectly input stimulationparameters for controlling the nature of the electrical stimulationprovided to the target spinal cord tissue, if not already set during anyintra-implantation trial stimulation period. When appropriate,post-implantation trail stimulation may be conducted, over one or moreweeks or months for example, and any necessary modifications madeaccordingly.

Although representative embodiments and advantages have been describedin detail, it should be understood that various changes, substitutionsand alterations can be made herein without departing from the spirit andscope of the appended claims. Moreover, the scope of the presentapplication is not intended to be limited to the particular embodimentsof the process, machine, manufacture, composition of matter, means,methods and steps described in the specification. As one of ordinaryskill in the art will readily appreciate from this disclosure,processes, machines, manufacture, compositions of matter, means,methods, or steps, presently existing or later to be developed thatperform substantially the same function or achieve substantially thesame result as the corresponding embodiments described herein may beutilized without departing from the scope of the appended claims.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

1. A paddle lead for implantation within the body of a patient fordelivering therapeutic electrical stimulation energy to target spinalcord tissue of the patient, the paddle lead comprising: a stimulationpaddle including a first insulative material; a plurality of electrodecontacts disposed on a first side of the stimulation paddle of thepaddle lead, the plurality of electrode contacts being adapted to allowthe stimulation paddle to flex transversely about a longitudinal axis ofthe stimulation paddle; a plurality of grooves disposed on a second sideof the stimulation paddle opposite to the first side, the plurality ofgrooves disposed substantially parallel to the longitudinal axis, theplurality of grooves running along a substantial portion of a length ofthe stimulation paddle; at least one of the plurality of groovesincluding a segment of a second insulative material with the secondinsulative material being of reduced durometer relative to the firstinsulative material of the stimulation paddle; a plurality of conductorsfor conducting electrical energy to the plurality of electrode contacts;wherein the plurality of electrode contacts are arranged in at leastfirst, second, and third rows that are disposed perpendicular to thelongitudinal axis of the stimulation paddle; the first and third rowsrespectively having multiple electrode contacts electrically coupled todifferent conductors of the plurality of conductors to enable themultiple electrode contacts of the first and third rows to function inindependent cathode states, anode states, or high-impedance states; thesecond row being disposed between the first and third rows, the secondrow having multiple electrode contacts each electrically coupled to acommon conductor of the plurality of conductors to cause the multipleelectrode contacts of the second row to function in a common cathodestate, anode state, or high-impedance state.
 2. The paddle lead of claim1 wherein the multiple electrode contacts of the second row are furtherdisposed in multiple columns such that the plurality of electricalcontacts do not enter multiple longitudinal areas of the first side ofthe stimulation paddle such that the stimulation paddle flexes at themultiple longitudinal areas.
 3. The paddle lead of claim 2 wherein atleast some of the plurality of grooves are disposed opposite torespective ones of the multiple longitudinal areas to facilitatetransverse flexing of the stimulation paddle.
 4. The paddle lead ofclaim 1 wherein the multiple electrode contacts of the second row areelectrically connected by exposed flexible conductive traces between theelectrical contacts.
 5. The paddle lead of claim 4 wherein the exposedconductive traces comprise multiple thin layers of conductive material.6. The paddle lead of claim 4 wherein the exposed flexible conductivetraces are disposed in a direction transverse to the longitudinal axisof the stimulation paddle.
 7. The paddle lead of claim 1 wherein themultiple electrode contacts of the second row are electrically coupledby a flexible conductive epoxy material disposed between the electrodecontacts of the second row.
 8. The paddle lead of claim 7 wherein theflexible conductive epoxy material is disposed in thin stripes, betweenthe electrode contacts of the second row, that are oriented in adirection transverse to the longitudinal axis of the stimulation paddle.9. The paddle lead of claim 1 wherein each electrode contact of thesecond row possesses a surface area of approximately three-fourths ofthe surface area of electrode contacts of the first and third rows. 10.The paddle lead of claim 1 wherein the first and third rows comprise atleast five independent electrode contacts.
 11. The paddle lead of claim1 further comprising: a first longitudinally oriented electrodeextending from at least the first row to the third row on a first edgeof the stimulation paddle; and a second longitudinally orientedelectrode extending from at least the first row to the third row on asecond edge of the stimulation paddle.
 12. A system for implantationwithin the body of a patient for delivering therapeutic electricalstimulation energy to target spinal cord tissue of the patient, thesystem comprising: an implantable pulse generator (IPG) for generatingelectrical pulses; and a paddle lead for delivering electrical pulsesfrom the IPG to target spinal cord tissue, the paddle lead comprising: astimulation paddle including a first insulative material; a plurality ofelectrode contacts disposed on a first side of the stimulation paddle ofthe paddle lead, the plurality of electrode contacts being adapted toallow the stimulation paddle to flex transversely about a longitudinalaxis of the stimulation paddle; a plurality of grooves disposed on asecond side of the stimulation paddle opposite to the first side, theplurality of grooves disposed substantially parallel to the longitudinalaxis, the plurality of grooves running along a substantial portion of alength of the stimulation paddle; at least one of the plurality ofgrooves including a segment of a second insulative material with thesecond insulative material being of reduced durometer relative to thefirst insulative material of the stimulation paddle; a plurality ofconductors for conducting electrical energy from a plurality ofterminals to the plurality of electrode contacts; wherein the pluralityof electrode contacts are arranged in at least first, second, and thirdrows that are disposed perpendicular to the longitudinal axis of thestimulation paddle; the first and third rows respectively havingmultiple electrode contacts electrically coupled to different conductorsof the plurality of conductors to enable the multiple electrode contactsof the first and third rows to function in independent cathode states,anode states, or high-impedance states; the second row being disposedbetween the first and third rows, the second row having multipleelectrode contacts each electrically coupled to a common conductor ofthe plurality of conductors to cause the multiple electrode contacts ofthe second row to function in a common cathode state, anode state, orhigh-impedance state.
 13. The system of claim 12 wherein the IPG isprogrammed to deliver first electrical pulses to target spinal cordtissue on the first row and to deliver second electrical pulses totarget spinal cord tissue on the third row to address chronic pain indistinct locations of the body.
 14. The system of claim 13 wherein theIPG is programmed to anodally block the first and second electricalpulses by setting the electrical contacts of the second row to an anodestate when the first and second electrical pulses are delivered to thefirst and third rows.
 15. The system of claim 12 wherein the multipleelectrode contacts of the second row are electrically connected byexposed flexible conductive traces between the electrical contacts. 16.The system of claim 15 wherein the exposed flexible conductive tracescomprise multiple thin layers of conductive material.
 17. The system ofclaim 15 wherein the exposed flexible conductive traces are disposed ina direction transverse to the longitudinal axis of the stimulationpaddle.
 18. The system of claim 12 wherein the multiple electrodecontacts of the second row are electrically coupled by a flexibleconductive epoxy material disposed between the electrode contacts of thesecond row.
 19. The system of claim 18 wherein the flexible conductiveepoxy material is disposed in thin stripes, between the electrodecontacts of the second row, that are oriented in a direction transverseto the longitudinal axis of the stimulation paddle.
 20. The system ofclaim 12 wherein each electrode contact of the second row possesses asurface area of approximately three-fourths of the surface area ofelectrode contacts of the first and third rows.
 21. The system of claim12 wherein the first and third rows comprise at least five independentelectrode contacts.
 22. The system of claim 12 further comprising: afirst longitudinally oriented electrode extending from at least thefirst row to the third row on a first edge of the stimulation paddle;and a second longitudinally oriented electrode extending from at leastthe first row to the third row on a second edge of the stimulationpaddle.